Raman Microspectroscopic Analysis of Selenium Bioaccumulation by Green Alga Chlorella vulgaris.

Selenium (Se) is an element with many commercial applications as well as an essential micronutrient. Dietary Se has antioxidant properties and it is known to play a role in cancer prevention. However, the general population often suffers from Se deficiency. Green algae, such as Chlorella vulgaris, cultivated in Se-enriched environment may be used as a food supplement to provide adequate levels of Se. We used Raman microspectroscopy (RS) for fast, reliable, and non-destructive measurement of Se concentration in living algal cells. We employed inductively coupled plasma-mass spectrometry as a reference method to RS and we found a substantial correlation between the Raman signal intensity at 252 cm-1 and total Se concentration in the studied cells. We used RS to assess the uptake of Se by living and inactivated algae and demonstrated the necessity of active cellular transport for Se accumulation. Additionally, we observed the intracellular Se being transformed into an insoluble elemental form, which we further supported by the energy-dispersive X-ray spectroscopy imaging.

Reactive Oxygen Species and Mitochondrial Dynamics: The Yin and Yang of Mitochondrial Dysfunction and Cancer Progression.

Mitochondria are organelles with a highly dynamic ultrastructure maintained by a delicate equilibrium between its fission and fusion rates. Understanding the factors influencing this balance is important as perturbations to mitochondrial dynamics can result in pathological states. As a terminal site of nutrient oxidation for the cell, mitochondrial powerhouses harness energy in the form of ATP in a process driven by the electron transport chain. Contemporaneously, electrons translocated within the electron transport chain undergo spontaneous side reactions with oxygen, giving rise to superoxide and a variety of other downstream reactive oxygen species (ROS). Mitochondrially-derived ROS can mediate redox signaling or, in excess, cause cell injury and even cell death. Recent evidence suggests that mitochondrial ultrastructure is tightly coupled to ROS generation depending on the physiological status of the cell. Yet, the mechanism by which changes in mitochondrial shape modulate mitochondrial function and redox homeostasis is less clear. Aberrant mitochondrial morphology may lead to enhanced ROS formation, which, in turn, may deteriorate mitochondrial health and further exacerbate oxidative stress in a self-perpetuating vicious cycle. Here, we review the latest findings on the intricate relationship between mitochondrial dynamics and ROS production, focusing mainly on its role in malignant disease.

A heat-stable hepatitis B vaccine formulation.

The purpose of the present study was to develop a formulation of recombinant hepatitis B vaccine with improved stability at elevated temperatures. A validated in vitro antigen reactivity assay was used to measure the stability of the vaccine. The formulation development focused on modification of the interactions between the antigen and aluminum hydroxide adjuvant and subsequent optimization of the ionic aqueous environment of the adsorbed vaccine. A formulation of hepatitis B vaccine containing 40 mM histidine and 40 mM phosphate at pH 5.2 had considerably improved stability at elevated temperatures as measured by the in vitro antigen reactivity assay. The formulation exhibited 9-week stability at 55 degrees C and was subsequently shown to be stable both at 37 degrees C and at 45 degrees C for at least 6 months based on the in vitro antigen reactivity and immunogenicity in mice. The formulation comprises only excipients which have a history of safe use in approved drug products. The new vaccine formulation has the potential to be used outside the cold chain for part of its shelf life. This may improve the immunization coverage, simplify the logistics for outreach immunization, and ensure the potency of the vaccine in areas where the cold chain is insufficient.